Apparatus for reforming hydrocarbons



Jan. 26, 1954 w. R. PIERCE APPARATUS FOR REFORMING HYDROCARBONS Filed Jan. 4, 1950 ATTORNEYS Patented Jan. 26, 1954 APPARATUS FOR REFORMING HYDROCARBONS Weller R. Pierce, Dumas, Tex., assignor to Phillips Petroleum Company, a corporation of Delaware Application January 4, 1950, Serial No. 136,742

5 Claims.

. This invention relates to improved method and apparatus for use in reforming hydrocarbon gases to produce gases containing hydrogen and carbon monoxide. In some of its preferred aspects it pertains to a control method whereby when natural gas or other methane-containing gas is reformed by reaction with steam in the presence of a catalyst in externally fired catalyst tubes the methane content of the resulting reformed gas is always maintained at alow value. In other specie and preferred aspects the invention pertains to particular control apparatus adapted for obtaining completely automatic control of a process of the type described. Among the important advantages of the invention is the fact that its use permits maximum production of synthesis gas (reformed gas) for a given apparatus and catalyst. l

Gases containing hydrogen and carbon monoxide nd several uses. Forexample, such a gas can be used as such for the catalytic synthesis of hydrocarbons by reaction of the hydrogen with the carbon monoxide in the presence of iron or cobalt catalyst; varying amounts of oxygenated hydrocarbon compounds can also be formed in such a synthesis. A gas containing hydrogen and carbon monoxide can be treated catalytically with excess steam to convert a large proportion of the carbon monoxide to carbon dioxide. This carbon dioxide can then be removed by known means, thus producing a gas high in hydrogen content. Such a gas containing large amounts of hydrogen can be used for fuel or industrial purposes, or by further supply of nitrogen thereto or to the original gas from which the hydrogen gas is produced, a gas mixture suitable for the catalytic synthesis of ammonia is obtained.

One such instance involves the reaction of natural gas with an excess of steam over a nickel or nickel oxide catalyst commonly referred to as a reduced nickel oxide catalyst disposed in a plurality of vertical catalyst tubes which are placed within a furnace. This furnace is fired by combustion of natural gas and the hot combustion products supply heat to the outside of the catalyst tubes. The resulting reformed gas is obtained with as low methane content as possible, since a large proportion of the residual methane ultimately appears in the process cycle gas in the ammonia synthesis step to be described. The reformed gas is next admixed with external air in a quantity suflicient to provide the desired amount of nitrogen for reaction with hydrogen to form ammonia, and the mixture passed through a secondary reformer wherein the oxygen content of 2 the air destroyed by reaction with hydrogen and with residual methane, thus introducing nitrogen to the system and at the same time reducing to some extent but not entirely the residual methane in the reformed gas. The resulting gas is passed through a shift converter wherein it contacts a catalyst at conditions such that the water gas shift reaction, occurs whereby carbon monoxide and steam react to form carbon dioxide and hydrogen. Carbon dioxide is scrubbed from the resulting gas by use of an amine solution or other known means, residual carbon monoxide is removed as by scrubbing with a cuprous salt solution, and the resulting ammonia synthesis gas composed essentially of 3 parts of hydrogen to one part of nitrogen and also containing small amounts, for example 10 per cent,of gases inert in the ammonia synthesis reaction including methane, argon, helium and other rare gases is compressed and reacted in the presence of a metallic synthesis catalyst in known manner to produce ammonia'. Ammonia is removed from the effluent, and a large portion of the residual gas is recycled to the ammonia synthesis reactor. Be-

cause the methane and rare gases become concentrated in the cycle gas, a portion thereof must be purged continuously or intermittently to avoid too high a build-up in the ammonia synthesis system.

By way of example, in the reforming process in an ammonia plant, natural gas treated for the removal of hydrogen sulfide and organic sulphur and heated to a temperature within the range of 400 to 440 C. is admixed with at least 100 per cent excess steam super-heated to a temperature of about 400 C. and passed over a reduced nickel oxide catalyst contained in a plurality of vertically disposed 25/20 stainless steel tubes. The.

steam to natural gas ratio is about 11.3 1 or greater, and the steam to reformed gas ratio is about 1.47zl. or greater (expressed as lbs. of steam per hour per cubic feet per minute of reaction gas). The gas volume ratio of steam to reformed gas in the total effluent, from the primary references is maintained at at least 0.5:1, and preferably at 0.611. The catalyst-containing tubes are stationed in a down-fired furnace wherein a reformed gas efuent temperature in the range 700 to '750 C. is maintained. The preferred temperature will depend on various factors including activity of catalyst and space velocites and in some instances can be higher than 750 C. In a typical plant from.10 to 12 vertical reaction tubes are disposed in a single furnace cell. Several of these cells are used, each cell being fed an individually 3 4icontrolled mixture of natural gas and steam, and termined by a thermocouple, said thermocouple each cell being red individually. A single plant takes over the control of the flow of fuel gas so may comprise one, two, or more units of six cells as to prevent further increase thereof with reeach. It is very important that as much as possultant overheating of the catalyst. Thus in sible of the hydrocarbon contentv of the natural 5 eiect the temperature controller activated by the gas be converted to carbon oxides and hydrogen. thelmOCOuple overrides the CODtIOl f the fuel Any methane contained in the reformed gas is IlOTmally maintained by the methane analyzer deleterious. to the subsequent ammoniasynthesis. Undermthe .CfCumStanCea-the methane anastep wherein the methane will build up in the syn'- lyzer then yproceeds to reduce the frate Oflatural thesis gas cycle around the converters and thus lo gas flow to the catalyst tubes S0 aS t0 Continue increase the amount of gas which must be purgedr.: tf` maintain a giVen predetermined maximum from the Cycle, It has been estimated that an mtehane content in the eiluent gas from the furincrease of 1 per cent in the methanecontent-'0f-A naCe 'Which S fnOW Operating at maXmum temthe reformed gas will result in a decreaseot* Derature.

about 6 per cent in animoniaipioduction.. Theref:- twll--ber appreciated by thOSe Skilled in the fore, the methane content oetheereformedigas@` art'thatfgVenlrmatelalS 0f Construction, given should never exceed about percent and should. Catalyst, and gVen reactants al1 may affect the preferably be below 2.5 per centi or'even' `.'LgiermaXnum v'desirabletemperature in a high temcent or less. At the higher values within :these i DelatlneV Operation Of the type described. Thus ranges an aci-,ive Catalyst for example reduced QQ the limiting factor may rbe the catalyst tubes, it

nickel oxideshould.beusedin.the.secondaryef.- may be the heat resistance Aofthe Catalyst, :Obit formersmtoadecrease .themethanecontent of the.. may' lbeth'e" heatTeSStanCefOfthe'"refaCtOreS final .synthesis gas. fr'omwyhicn'the'furna'ce ris made or with"whi'c`h`-t iiiaanobieei.ofaiiiainveniioaiolprovieaan. inedj Reaction fates andfthermodvnamiewn: improvedmeansoi" controlfonareforinng,proc, 25 sldefatlOnS Inay alSO play.apartinnhoce'nfa ess wherein ahydr'ocarbongas. iscOnVerted .by eslred; tmaxlnum temperature; .Il 'the present* reactionAWith' Steamnm hydrogen and carbgn invention,itisipreferredito lde'tectthe tempera# mgnoxdeM ture of the reformed VVVgas `justasitl leavesth'e Authe @10J-eci;` @f th invention iSJtO prove, catalyst tubes or immediately'aft'er'exit fromtthe improved Vcontrol apparatus for controlling suoli` flllnace DYOPeTl HOJVeVeI;rr temperature"detec-v` a pmssw tion can be obtained at variousother-pointsin" Ahoi-,her Object swtpmvdeha inovel:method` the system wherein the teinperature'eisdirectlyj off.controlwh'ereb'yI the; maximum -permissible related to the tem@wwwotmellie'llel methaneicontentbf thelfrefo'rzned gas. isiieverv formed fasi 'Ifhlle 'the-temperature 'atfonefor exceedejdand yetthegreatestpossiblethroughput morepomts Wltlm the`furnace^`itse1ff mMthe iseat. alllltimesmaintained 'inthefreforinng..sysv temperaturewlthm a' catalyst tubeitselfor the" temr o external temperatureof catalyst;tubesfmay`fall' A fiirtiieii. obieoi. eigene.inventioriiaio -proa be employedv as controlled @imams-desired.; orne-1A vide speci@ comrollmachanisms* pmtwmuyA viously for a desired maximum temperaturernff adapted.to.. insure. adequatefreaction. onatural. i0 emufenp'relormed gasof Saytqocvci if the control point'is within fthe furnace proper-fitfwill' be eon=- gasoitbther.hydrocarbon..gas.,beingreformedL catalyticalljin the presenceeof steam.in..exter.- slclerbl? .higher Itwmalsbe learqthose';

naiiy ,fiieiizoaiaiysi tubes, ,and yet. avoid .iincaisirf Skmed inggthe art Once' i hel/.mg been "gwenf'thei present disclosure, thatvarious typesfof thermo` ablyhigh temperatures.

Frther .Objects.and-.advantagesof the im/emi couples; recorders.- controllers;-methanefanalyz#- ers', andv similar instrumentsfas required 'canfbez tionwill .beapparenh to .one skilled .in .thf=i.art,` from theaccompanying. disclosuraand.ldiscusff employed Wlttloutvdepartmg ffomethe 'bmad sccpe sion* of the invention.' Valves in fuel gas lines andfiinr While the invention win be described., with: the'lydmcarbon'feedgas hnesmay'be-@Pyco' particular referenceto. the reforningbi natural Ventlonal type of .m0,t0r:Valvefoprertd:.etthetmf gas, ii wiiibe..e1eai. to.tiiose skilled inthe arr thatv response 130.15m? 'Varymg presureof a 'm man* other hydrocarbon w materials., madly termed strurrient: air line :by'known.meansoroperated hereinhydrocarbon gasesbut whichlmay be norelectnca'uy kllownl meansas determmedby mauy-ugaseous`or normallynldud .asrdesdal the* controlling instrumentsxemployed. Inase't` though' gaseous. while undergoingreorming,,ref 55 much as' such A motor'jvatvesm thermocouplese: action, may be employedy viileconomically warmethane analyzers" controt'ltlstrumentrespon?" ranted in Ya ,particularsituation... Natural gas is. SW6 to temmrmurevv fn' 'varymg the'settmgofaj byar the* most, common hydmcarbon v ed to valve;V and-. i contrnlinstruments; :'responsive1gto: the reforming processmethane content for :vary-ing ztheesettinggof' ita The present inventioinprovides a.control .'sys- 60 vglye 'aire au Wenknowgjoth-'art m1-heul teni Wherebyit is'. possibletoipasslthe maximum. dwldllal frmsi construtwn 'cff'lsante munot beef amountof. naturaljgasto agivemreforming. furdescmbed' mi great 'detaufermas lt Wouldlomy nacewithoutexceedinga predetermined methane; Srve to burqenftheh desfcrlpttoniof. themventlfm contentinth'eeluent refdrined gasand without Wlthout adding to.-. the..y clarity thereof. While'.i exceedigxa pl.edetermnedmaximum tempera 65 natural gasfis described `asthepreferred fuel'ato:

tureinthe furnace.-. In a specic embodiment of the furnaces 'other liquid '01' even Solid fUelSfCanlf' this invention, a methane analyzer, for example be employed inkhown-manner, theirratofnasa an infra=red spectrophotometer;continuously'deJ Sage t0 the furnace fOI VeOlnlOuStOn fbe-ng suitably* termines and records the methane noni-,ent 'of i;yffeV controlled in a manner which`will"'be"obvious,to reformed gas effluent and continuouslyadjusts the 70 these Skilled in the alt:y

rateof'fuerinput yto the reforming furnace so as- A preferred embodiirient 0f the present'invento maintainthe .desired V.methane contentin'fthe: tion sshown in "thesaccompanying drawing eiliient. reformedggas. Whenthe Aabove" pro- Whichis afschematicdiagramsof-apparatus'felececlure hasraisled thetemperatureof.,the eiiient. ments `arid'iioiv -of materials "therethrough-*teef fromthefurnacato. apredeterniinedlevel as degethr' with'ithe essentialy 'control"instrumentar suitable for practicing the invention. I'he drawingand the description thereof will serve to exemplify the invention. Various modications of the speciiic arrangement and elements .can be made by those skilled in the art without departing from the invention.

In the drawing, natural gas from any suitable source is introduced through line I0 and its pressure reduced to a fixed value, for example 80 pounds per square inch gauge, by means of a standard pressure reducing valve I2 made responsive to the downstream pressure by control line I4. This natural gas is the source both of the fuel gas and the reaction gas which is to be reformed. Reaction gas is passed via lines I6 and 24 to the catalyst tubes 26, the flow of gas through line I6 being controlled by a conventional motor valve I8 of any desired design. Steam is introduced into the reaction from line at a rate fixed by valve 22. This rate is chosen so as always to be in excess of the quantity stoichiometrically required for the reforming of the maximum quantity of reaction gas which can be passed through the system. The mixture of steam and naturalgas is passed via manifold 24 into a group of catalyst tubes shown diagrammatically by the three vertically positioned catalyst tubes 26 in the drawing. These are placed in a furnace 28 made of or lined with suitable fire resistant refractories. Means (not shown) are of course provided for introducing catalyst into the catalyst tubes and for dumping the catalyst therefrom when it has become unsuitable for further use. Reformed gas,vcomposed largely of hydrogen, carbon monoxide, carbon dioxide, and steam, together with residual unreacted hydrocarbons, largely methane, are withdrawn from the catalyst tubes through line 30and passed to further treatment as described hereinabove.

-The fuel gas is withdrawn fromline I0 via line 32, and passes through motor valve 34 and motor valve 36 to line 38 and then to the burners-40. These burners are of any conventional type and are shown disposed in the top of the furnace in air openings 42 adapted to supply the necessary air for combustion. The hot combustion gases leave the furnace at the bottom through opening 44 and pass to the stack in conventional manner, first going through Waste heat boilers for production of steam if desired.

By way of example, a typical natural gas fed to the process as reaction gas and as fuel gas is as follows:

CO2 0.12 N2 (including rare gases) 16.67 CHi 71.56 C2 5.73

C3 3.55 'C4 1.69 C5 0.45 06+ 0.23

Total 100.00

CO2 12.9 CO 7.0

H2 CH4 3.3

Total 100.01

Turning again to the drawing, a methane an- I alyzer 46 is shown diagrammatically. This methane analyzer may take any suitable form, and its operation might for examplebe based on thermal conductivity measurements, combustion of residual methane (although this is less suitable because of the low methane content), or infrared spectrophotometric analysis. The latter is preferred, and in such case a small stream of the effluent gas to be analyzed for methane is continuously lead from exit line 30 via line 48 at a fixed rate controlled in known manner and passed through a cell in the methane analyzer 46 through which is passed a beam of infra-red radiation. The gas thus used is then passed to the atmosphere through line 50 or if desired returned to admixture with the balance of reformed gas. The proportion passing through the cell of infra-red light of the wave length which is absorbed by methane is measured photometrically and the methane content thus constantly determined. In a large plant in which several cells of catalyst tubes are used and are thus to be controlled individually, a single methane analyzer of the type described can be used, with gas from each cell being sampled in turn and the results transmitted to the respective control systems on a vtime cycle basis through the use of known time cycle devices. The methane analyzer is calibrated so that for the range of methane contents anticipated a suitable corresponding range of air pressures can be supplied in the instrument air line leading from the methane analyzer to the control instruments. Instrument air is supplied to the methane analyzer at a constant pressure, forv example 30 p. s. i. g., and this pressure is reduced in known manner, for example by a conventional variable reducing valve, as required. The analyzer 46 thus causes the air pressure in instrument air line 52 leading from it to the control instruments to vary as a function of the methane content of the reformed gas in conduit 30. The instrument air line 52 leads by Way of line 54 directly to motor valve 34, and by way of line 55 to motor valve IB. In line 5S is placed a pressure controller 58 which is responsive to the air pressure in line 52 and is pre-set to become operative for pressuring control air into line 5S whenever the control air pressure in line 52 reaches a predetermined maximum value which is the value at which motor valve 34 is completely open or at least largely open.

Temperature controller 60 is indicated in the drawing diagrammatically, and it may be of any conventional type. It operates in response to a thermocouple 62 which is shown detecting the temperature of the eiiluent reformed gas in line as.- iridicateriabore,` thetemperature control vpoint;

at..which. therrnocoupleY 62 is placed may. be else-f Motoryalvei is'set With'the Acontrol air onv the' side 'ofthe diaphragrn'wh'ich will Acause the motor valveto 'close'with increasedpressure and open Withidecrease'd' pressure. Motor' valve i8 inthe reactionzgas line. ISis' 'alsoj so set, Whereas motor valve Sain-fu'el"gasline32is'oppositely set so that increased air"pressure/ininstrument control line .'dopens'valve-S 'and decreased control pressure` closes it. Y

While 'the operationpf thecontrols will be described lwith reference to what happens asthe methane 'content ofthe reformed Vgas tends to increase'and .the controlsftake steps to prevent the increase above the Vpredetermined set point, itwillbe clear .to those skilled in the art that as theopposite happens, i.e..as the methane content'oi the reformed Ygas. .tends to decrease, the controlsoperate in opposite-.sequence in order to decrease vtheseverity "of Y"reforming "and thus maintain themethanexcontent of the reformed gases in'a chosen. narrowrange.' Ther controls permit 'at allti'rnes' th'emaximum possible quantit-y lof vreaction 'gas tobe passed through'line I6 into the catalyst tubes 'so'as to'obtain the'maximum' throughput for .the"systern, limited only by the methane content' V'oi the reformedgas and the maximum Atemperature which the system will withstand, about '750'"C." as indicated hereinabove.

increasing the Vheat liberated.inthe'furnace and u thus fincreas'in'g'the severity of thev 'reforming 'reaction. This will"te'nd"to'reducelthe methane content ofthe elent." Should the methane 'content Icontinue to rise,.rnotor 'valve 'isfurther" opened 'to provide .'additional fuel' gas. Th'eincreased fuel gas', by increasing 'the heat input 'to' the vcatalyst'tubes',v decreases 'the methane'con'- tent, of thfe'eluent gas." Asth's decreases, the' motora'alved of course acts in the opposite direction' cutting back" the fuell gas" somewhat.

However, when conditionslfor' example catalyst.

activity, are suchA thatv the increased' heat input fails 'to reduce the methane content suiciently,

the furnace temperature increases since the heat is not being takenuplbygthe endothermic reformingreacti'on. SoY longjas the vtemperature -control point does .not exceedthepre-set value," representing. a Achosen value between 700 and '750 C. for. the reformedgas outlet temperature, temperature controller 6!) is inoperative. However when thetemperature control point reaches the maximum :te1nperature;` l temperature-'controller EB takesover-and as fsoonas the temperature-.in-

creasessabove'ttheepre-set .value provides-/vanl-.increasedcontrol airrp-ressure lin'e 66 Whichzacts-z Samara redeceiheeuanamonfueiagasentenng onathediaphragmiofmoto valyesanchthrott'l methane montent-:ofi: the ,eiiinertfieiormedugasifi lineiiiv` to. :continue Ato: increafs'er.v As this; occur the iairt controll pressure: .inliries 5 i'andzl con tinues to increase butr motoivalve' iis alreadysat' kits finaximum fopeninggwheruponpre'ssure:icon f 1 with 'the diaphragm of' ymotor valvfi 3 'in "the" reeTv action-'gas inleta Val-ve |8"then beginsf'fto closer responsiveto YVthe vincreased'.pressure 1in Nzcr'untr'ol line 56.' This throttlingeof'vvalve I8 'and-lhenceif reducing fthe arnountwof naturali =gas Y:ifedto' the catalyst :tubes continues so longgfasI the? methane'rf content ofi;` the f eiiluenti irefo'r'm'ed' .-'gasY-tendstf increase above*r the` prede'termineri1Y maximums value. Itv 'I will' beI 'apparentfthat this? operation will bring. thev 'reaction-fito: 'thefdesiredistateof conversion fwhen the :supplyiofcfuel 1 gas! has :.beenp. increased 'f as muchf as' possiblenbyf motor valve#lf-'fiA butthis has been overriddenf-by motor'fvalve 13W in` order/to Vavoid Vundesirably:high*furnace iterni-TvM perature;

While motorr valve' 35 "responsive rftoA temperature has" ibee'n'i shown-'Tasa valve separate fronfi" valve f34rres'ponsiv'e :tof methane :content'jf being in the fuel gas'line,l valve nay if de ired' be dispensed iWitli and motorvvalve'- 34? E'chos'eiias' a Vthree-way oroverwontroly valve fof kniiwn" type? Suona-valve'is'arranged to operateur.'the mannerfdescrib ed" withfrespect toY the twovallves l 34 #and .36; so .that when; the valve isope'nedasv farli:v as fdetermined in aizlvance'ito1 be -desirableby a'ir ypressure from instrumenticontroliliiie llli'-'tlliis'' actionfwillibe `2over-riddenfbyf increased pressure ofcontrol air finvline B''Wh-ichinl thisV instance would be also connected to valve 34 inliknown' manner. While air control of the motor valves ,has ybeendesc-:ribedthose-skilled-in the .art` willappreciate that-analogous electrical controls may be 'elnplo-yed -Whereinfthe motor -valves are operated-i by -solenoidsor otherwise-in response -to varying-voltage or current-in 4electr-icalcontrol lines-Which areconnectedwithmethane analyzer action with 'steam toproduce'i a'refrined gas' con-'- i taining hydrogen and carbon monoxide, said systern including a furnace containing a plurality of externally red -catalyst tubes, fuel supply means for introducing fuel to the furnace, a conduit for supplying steam to the catalyst tubes, a conduit for supplying hydrocarbon gas to be reformed to said catalyst tubes, and a conduit for withdrawing reformed gas from said catalyst tubes, said apparatus comprising at least one control means on said fuel supply means for controlling the quantity of fuel supplied to the furnace, a control valve on the conduit supplying hydrocarbon gas to be reformed to the catalyst tubes, a hydrocarbon gas measuring device for determining the quantity of unreacted hydrocarbon gas present in the aforesaid reformed gas conduit, a temperature measuring device for measuring a temperature within the system which is directly related to the reaction temperature, a controller adapted to control said fuel supply responsive to the measured hydrocarbon content of the reformed gas whereby the lfuel supply is increased as the said hydrocarbon content increases, a controller responsive to the aforesaid measured temperature adapted to override the last mentioned fuel supply controller suflicient to avoid an increase in temperature above a predetermined maximum value by throttling the supply of fuel, and a supplemental controller operative to throttle the aforesaid valve on the conduit supplying hydrocarbon gas to the catalyst tubes responsive to the measured hydrocarbon content of the reformed gas Whenever same tends to increase above a predetermined maximum value and the fuel supply controller which is responsive to the hydrocarbon gas content of the reformed gas is being overridden by the said temperature controller.

2. Apparatus according to claim 1 wherein said controller responsive to said measured ternperature is responsive to a temperature measuring device mounted upon said conduit withdrawing reformed gas from said catalyst tubes and is adapted to measure the temperature within said conduit.

3. Apparatus according to claim 1 wherein the means for supplying fuel is a conduit carrying a fuel gas, said fuel supply controller is a valve in said conduit, and said overriding controller is a separate valve in said conduit.

4. Apparatus according to claim 1 wherein the means for supplying fuel is a conduit carrying a fuel gas, said fuel supply controller is a valve in said conduit, and said overriding temperature control is operated to throttle said last named valve.

5. Apparatus according to claim 1 wherein the means for supplying fuel is a conduit carrying a fuel gas, said fuel supply controller com'- prises an air-operated motor valve in said conduit, the control valve in the line supplying hydrocarbon gas to the catalyst tubes is an airoperated motor valve, and wherein said apparatus comprises a single control air conduit connecting the hydrocarbon gas analyzer with the last two named motor valves said analyzer being adapted to increase the pressure in said control air conduit in response to an increase in measured hydrocarbon content and decrease said pressure in response to a decrease in measured hydrocarbon content, the first said motor valve in the fuel supply line is adapted to open proportional to increased air pressure in said control conduit and a pressure responsive valve interposed in the control conduit leading to the motor valve in the reaction gas supply line pre-set so as to open and thereby supply pressure control air to the last named valve to throttle same whenever the pressure of control air from said hydrocarbon analyzer increases to a value in excess of that which will cause further opening of the fuel supply motor valve.

WELLER R. PIERCE.

References Cited in the le 0f this patent UNITED STATES PATENTS Number Name Date 1,904,592 Young et al. Apr. 18, 1933 1,904,593 Young et al. Apr. 18, 1933 2,171,596 Parker Sept. 5, 1939 2,172,106 Parker Sept. 5, 1939 2,173,984 Shapleigh Sept. 26, 1939 2,258,146 Pontow Oct. 7, 1941 2,262,427 Lieclholm Nov. 11, 1941 2,430,432 Marisic Nov. 4, 1947 2,463,115 Legatski Mar. 1, 1949 2,565,395 Scharmann Aug. 21, 1951 

1. APPARATUS FOR CONTROLLING THE OPERATION OF A SYSTEM FOR REFORMING A HYDROCARBON GAS BY REACTION WITH STREAM TO PRODUCE A REFORMED GAS CONTAINING HYDROGEN AND CARBON MONOXIDE, SAID SYSTEM INCLUDING A FURNACE CONTAINING A PLURALITY OF EXTERNALLY FIRED CATALYST TUBES, FUEL SUPPLY MEANS FOR INTRODUCING FUEL TO THE FURNACE, A CONDUIT FOR SUPPLYING STREAM TO THE CATALYST TUBES, A CONDUIT FOR SUPPLYING HYDROCARBON GAS TO BE REFORMED TO SAID CATALYST TUBES, AND A CONDUIT FOR WITHDRAWNG REFORMED GAS FROM SAID CATALYST TUBES, SAID APPARATUS COMPRISING AT LEAST ONE CONTROL MEANS ON SAID FUEL SUPPLIED MEANS FOR CONTROLLING THE QUANTITY OF FUEL SUPPLIED TO THE FURNACE, A CONTROL VALVE ON THE CONDUIT SUPPLYING HYDROCARBON GAS TO BE REFORMED TO THE CATALYST TUBES, A HYDROCARBON GAS MEASURING DEVICE FOR DETERMINING THE QUANTITY OF UNREACTED HYDROCARBON GAS PRESENT IN THE AFORESAID REFORMED GAS CONDUIT, A TEMPERATURE MEASURING DEVICE FOR MEASURING A TEMPERATURE WITHIN THE SYSTEM WHICH IS DIRECTLY RELATED TO THE REACTION TEMPERATURE, A CONTROLLER ADAPTED TO CONTROL SAID FUEL SUPPLY RESPONSIVE TO THE MEASURED HYDROCARBON CONTENT OF THE REFORMED GAS WHEREBY THE FUEL SUPPLY IS INCREASED AS THE SAID HYDROCARBON CONTENT INCREASES, A CONTROLLER RESPONSIVE TO THE AFORESAID MEASURED TEMPERATURE ADAPTED TO OVERRIDE THE LAST MENTIONED FUEL SUPPLY CONTROLLER SUFFICIENT TO AVOID AN INCREASE IN TEMPERATURE ABOVE A PREDETERMINED MAXIMUM VALUE BY THROTTLING THE SUPPLY OF FUEL, AND A SUPPLEMENTAL CONTROLLER OPERATIVE TO THROTTLE THE AFORESAID VALVE ON THE CONDUIT SUPPLYING HYDROCARBON GAS TO THE CATALYST TUBES RESPONSIVE TO THE MEASURED HYDROCARBON CONTENT OF THE REFORMED GAS WHENEVER SAME TENDS TO INCREASE ABOVE A PREDETERMINED MAXIMUM VALUE AND THE FUEL SUPPLY CONTROLLER WHICH IS RESPONSIVE TO THE HYDROCARBON GAS CONTENT OF THE REFORMED GAS IS BEING OVERRIDDEN BY THE SAID TEMPERATURE CONTROLLER. 